How dangerous is heart rate of 228 in older cat

[mathsfiend1]

Just that really. Is this something that needs urgent attention? Thanks.

I suppose it's a little high. Did you check it or a vet? When in doubt, take your cat to the vet. That's the rule I tend to live by. Is your cat ok?

Went to vet - charged £110 (!) for a blood test and this is all I have been told. Thanks.

Didn't vet recommend treatment or give any idea of what to expect? I think I'd call vet or pop into them and explain that you're concerned and confused by the info they've given you and you'd like to clarify exactly what the next step is for your cat. It sounds as if they've not been clear with you. If there are any vets here, maybe you could offer advice?